We present a mirrored atomistic and continuum framework that is used to
describe the ignition of energetic materials, and a high-pressure phase
of RDX in particular. The continuum formulation uses meaningful averages
of thermodynamic properties obtained from the atomistic simulation and a
simplification of enormously complex reaction kinetics. In particular,
components are identified based on molecular weight bin averages and our
methodology assumes that both the averaged atomistic and continuum
simulations are represented on the same time and length scales. The
atomistic simulations of thermally initiated ignition of RDX are
performed using reactive molecular dynamics (RMD). The continuum model
is based on multi-component thermodynamics and uses a kinetics scheme
that describes observed chemical changes of the averaged atomistic
simulations. Thus the mirrored continuum simulations mimic the rapid
change in pressure, temperature, and average molecular weight of species
in the reactive mixture. This mirroring enables a new technique to
simplify the chemistry obtained from reactive MD simulations while
retaining the observed features and spatial and temporal scales from
both the RMD and continuum model. The primary benefit of this approach
is a potentially powerful, but familiar way to interpret the atomistic
simulations and understand the chemical events and reaction rates. The
approach is quite general and thus can provide a way to model chemistry
based on atomistic simulations and extend the reach of those
simulations. Published by AIP Publishing.